(1) Field of the Invention
The present invention relates to a disk apparatus in which one of a CD-ROM and a disk cartridge is held on a disk tray at a loaded position and reproduction or recording for a related disk is carried out by using a pickup unit.
(2) Description of the Related Art
An optical disk is inserted into an optical disk drive, and the optical disk drive reads information from or writes information to the optical disk by using an optical pickup unit. The optical pickup unit emits a light beam to the disk and receives reflection beams from the disk to which the emission beam is applied. When the optical disk drive is operating in a reading mode, the optical pickup unit detects pits in a track of the disk from the reflection beams in order to read data from the disk.
Recently, there are two major types of optical disk drive: a read-only type and a rewritable type. The read-only optical disk drives read information from an optical disk, such as CD (compact disk) and CD-ROM (compact disk-read-only memory). The rewritable optical disk drives can read information from and write information to an optical disk. Among the rewritable optical disk drives are a write-once disk system and an erasable disk system. The write-once disk system accesses an optical disk such as a CD-R (compact disk-recordable), and can write data to the disk once only. The erasable disk system accesses an optical disk, such as a PD (phase-change material disk) or CD-RW (compact disk-rewritable), and can write data to the disk many times.
Existing optical disk drives are provided for accessing only one of the above-mentioned optical disk types. In order to allow both the read-only disk (CD, CD-ROM) and the rewritable disk (CD-R, PD, CD-RW) to be accessed, it has been necessary to use two or more of the existing optical disk drives in combination. Recently, in order to eliminate such inconvenience, development has started on an optical disk apparatus in which either one of the read-only disk and the rewritable disk can be held on a disk tray at a loaded position and reproduction or recording with respect to a related disk can be carried out. A conventional disk apparatus of this type is known. In the conventional disk apparatus, one of a CD-ROM and a PD disk cartridge can be held on a disk tray at a loaded position and reproduction or recording with respect to a related disk can be carried out.
FIG. 26 shows a disk tray 1 of the above-mentioned conventional disk apparatus. On the disk tray 1, either a CD-ROM 9 or a PD disk cartridge 10 can be held at a loaded position. FIG. 27 is a cross-sectional view of the disk tray 1 on which the CD-ROM 9 is placed. FIG. 28 is a cross-sectional view of the disk tray 1 on which the disk cartridge 10 is placed. The disk cartridge 10 contains an optical disk 10a as shown in FIG. 28.
As shown in FIGS. 26-28, the disk tray 1 has a double-tray structure including an inner tray 2 on which the CD-ROM 9 is placed and an outer tray 3 on which the disk cartridge 10 is placed. The inner tray 2 is provided within the outer tray 3 such that the inner tray 2 is vertically movable between a lowered position and a raised position.
The inner tray 2 includes a first circular recess 2a to which a disk having an 8-cm diameter is fitted, and a second circular recess 2b to which another disk having a 12-cm diameter is fitted.
In the disk tray 1 of the conventional disk apparatus, the inner tray 2 is normally set at the raised position as shown in FIG. 27, and, when the CD-ROM 9 is inserted in the disk tray 1, the CD-ROM 9 is supported on the inner tray 2 at the raised position. When the disk cartridge 10 is inserted in the disk tray 1, the inner tray 2 is vertically moved to the lowered position as shown in FIG. 28, and the disk cartridge 10 is supported on the outer tray 3.
In the disk tray 1, a tray moving mechanism 4 is provided to vertically move the inner tray 2 within the outer tray 3. The tray moving mechanism 4 includes a pair of pressing rods 5, a pair of helical compression springs 6, two pairs of guide grooves 7, and two pairs of pins 8.
The pressing rods 5 and the helical compression springs 6 are provided on a rear wall of the outer tray 3. The pressing rods 5 press the inner tray 2 in a direction indicated by the arrow "A" in FIGS. 26-28. The springs 5 exert an actuating force on the pressing rods 6 such that the inner tray 2 is pressed by the pressing rods 5 in the direction "A".
The guide grooves 7 are provided at two positions on each of right and left side walls of the outer tray 3. The pins 8 are fixed to each of right and left side walls of the inner tray 2 at two positions which correspond to the positions of the guide grooves 7. The pins 8 extending sideways from the inner tray 2 are fitted in the guide grooves 7.
As the inner tray 2 is pressed by the pressing rods 5 in the direction "A" due to the actuating force of the springs 6, the pins 8 are normally placed at upper ends of the guide grooves 7. Therefore, the inner tray 2 is normally set at the raised position as shown in FIG. 27. When the CD-ROM 9 is inserted in the disk tray 1, the CD-ROM 9 is supported on the inner tray 2 at the raised position.
When the disk cartridge 10 is inserted in the disk tray 1, the inner tray 2 is vertically moved to the lowered position by the disk cartridge 10 as shown in FIG. 28. At this time, the pins 8 are moved downwardly along the guide grooves 7 to lower ends of the guide grooves 7 by the disk cartridge 10, and the pressing rods 5 are pushed against the actuating force of the springs 6 in a direction indicated by the arrow "B" in FIG. 28 by the downward movement of the inner tray 2. Therefore, the disk cartridge 10 is supported on the outer tray 3.
As shown in FIG. 27 and FIG. 28, in the disk tray 1 of the conventional disk apparatus, the inner tray 2 is vertically moved between the raised position and the lowered position within the outer tray 3, such that the loaded position for the CD-ROM 9 and the loaded position for the disk 10a of the disk cartridge 10 are the same as each other.
However, in the above-described disk tray 1, the inner tray 2 has to be set at the lowered position and included beneath the disk cartridge 10 in the outer tray 3 when the disk cartridge 10 is inserted. Therefore, as shown in FIG. 28, it is necessary that the entire thickness "La" of the disk tray 1 is greater than a sum of a thickness "Lb" of the disk cartridge 10 and a thickness "Lc" of the inner tray 2 (La&gt;Lb+Lc).
In the conventional disk apparatus, it is impossible to reduce the entire thickness of the disk tray 1 (or the thickness "La" of the outer tray 3) below the sum of the thickness "Lb" of the disk cartridge 10 and the thickness "Lc" of the inner tray 2. This makes it difficult to provide a thin structure for an optical disk drive installed in a personal computer. In recent years, notebook-size personal computers having a built-in optical disk drive as standard equipment are widespread, and there is a demand for reducing the entire thickness of the built-in optical disk drive for use in the notebook-size computers.